Stellar and planetary systems at late stages of stellar evolution
Sonja Schuh
Georg August University Göttingen
The number of known planetary systems beyond the main sequence are
sparse so far, yet they are relevant for mapping the full parameter
space of planet formation and evolution. The pulsation timing and the
eclipse timing methods are highlighted as particularly suitable
approaches to search for planets around evolved stars. Both extrasolar
planet searches and asteroseismology, while at the same time strongly
relying on modeling, are very much observationally driven at the moment.
Their increasing synergies are partly thanks to the convergence on the
instrumentational side. This applies to ground-based as well as, to an
even higher extent, to space-based surveys. The EXOTIME program,
conducted from ground-based telescopes, covers a niche that exploits
stellar pulsations of a particular type of evolved stars to search for
planets and low-mass/substellar companions with the timing method, as
well as to use the pulsations to characterize the host stars. One of
EXOTIME's main science drivers is the after-the-fact investigation of
star-planet interactions during the red giant phase, an evolutionary
stage where an evolving host star and some of its planets are likely
to interact in a way that may even imply direct consequence for the
structure of the star, and certainly for the planet. The specific
experience from the on-going EXOTIME observations and analysis can be
drawn upon to extend the synthesis of pulsation timing for planet
searches, and pulsation analysis for host star characterization, to
the space-based KEPLER data. Rapidly and strictly coherently pulsating
stars such as those used in EXOTIME are very rare even in the vast
amounts of KEPLER data sets that are now continuously coming in. The
unique coverage and signal-to-noise ratio of the KEPLER data, however,
will allow to explore an extension of the timing method to other types
of variable stars. Its application can also encompass variability due
to eclipses instead of, or in addition to, pulsations. A broadening
in scope will in the long term also be useful to take advantage of the
data from the proposed future PLATO mission, with its ambitious goal
of asteroseismic, photometric and (using ground-based follow-up
observations) spectroscopic full characterization of systems.
Date: | Vendredi, le 18 février 2011 |
Heure: | 14:00 |
Lieu: | Université de Montréal |
| Pavillon Roger-Gaudry, Local Z-300 |
Contact: | Pierre Bergeron |
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